Method for manufacturing an electromechanical structure and an arrangement for carrying out the method

ABSTRACT

A method for manufacturing an electromechanical structure includes producing conductors on a flat film and estimating a strain that a plurality of locations on the flat film will undergo during formation of the flat film into a three-dimensional film. The method further includes attaching electronic elements on the flat film at selected locations of the plurality of locations on the flat film. The estimated strain of the selected locations of the plurality of locations is less than the estimated strain in other locations of the plurality of locations. The method further includes forming the flat film into the three-dimensional film and injection molding material on the three-dimensional film.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a division of U.S. patent application Ser. No.16/018,127, filed Jun. 26, 2018, now U.S. Pat. No. 10,575,407, which isa continuation of U.S. patent application Ser. No. 15/813,397, filedNov. 15, 2017, which is a continuation of U.S. patent application Ser.No. 15/030,883, filed Apr. 21, 2016, now U.S. Pat. No. 10,660,211, whichis a national stage application of International Patent ApplicationSerial No. PCT/F12014/05072, filed Sep. 25, 2014, which claims thebenefit of U.S. Provisional Patent Application Ser. No. 61/883,484,filed Sep. 27, 2013. The entire disclosures of each of which areincorporated herein by reference.

FIELD OF THE INVENTION

Generally the present invention concerns electromechanical structuresincorporated in electronic devices. Particularly, however notexclusively, the invention pertains to a method of creatingthree-dimensional single substrate electromechanical structures withembedded components and elements.

BACKGROUND INFORMATION

Manufacturing methods of different electromechanical devices haveimproved tremendously specifically as mobile devices and such withfeatures, such as sophisticated displays and interactive/responsivecovers, have become more commonly used consumer appliances. Such devicesincorporate sophisticated touchscreens, touch surfaces and the like withnumerous functionalities, which in turn, requires using different, andoften delicate, components.

The ever increasing user needs for large variety of functionalities andintuitiveness of products have helped to create a situation where a userdoesn't want the device to limit their use. Instead, all the devicesshould be more enabling than restricting to use in a way that isinstantly intuitive.

At the same time, the need for more agile and flexible manufacturing hasbecome increasingly evident since the outer design of devices as well asthe components used inside have needed to develop and change along withdynamic market needs.

This creates a real need for a manufacturing process that enablesincorporating various different components in relation to the housingstructure, be it two- or three-dimensional.

Although components have become increasingly smaller and more flexiblemany of them are still relatively bulky compared to printed electronics.Printed electronics have shown the way to thin, flexible and rapidlymanufactured structures but a vast amount of components cannot still bemanufactured by printing.

Also, creating three-dimensional substrates and housing structures withembedded electronic components is presently done by first shaping thesubstrate and then attaching the components to the ready-shapedthree-dimensional substrate. Attaching components on suchthree-dimensional substrates creates a disadvantageous situation wherecomponents are attached on inclined surfaces, which creates inaccuraciesand is also otherwise difficult and time-consuming from themanufacturing perspective especially when compared to the process wherecomponents are attached on a flat surface.

Some other methods propose placing components on a substrate (ontopreferred locations) and then molding over the substrate, which thenfunctions as an insert; method which is in most cases carried out byinjection molding. This method is prone to many mistakes and failuresbecause the components need to be placed highly accurately in correctplaces and then kept there throughout the molding process. Anotherdifficulty of this process is the somewhat violent temperature changescaused by the molten material as it cools down. Together theserequirements lead to a very difficult situation, wherein a lot of faultyunits do occur. Even further, this method doesn't provide the means fora truly three-dimensional shaping as the substrate, which is used as aninsert, doesn't considerably change its shape during the process.Moreover, each mold can be only done once; after the substrate and thecomponents therein have been overmolded the shape and thecircuit-component structure is set so it isn't possible to fix flaws.

Some other manufacturing processes comprise using laminated surfacesthat consist of a number of layers or substrates piled and attached oneach other. These methods however also embody disadvantages, such as thelimited malleability from flat to three-dimensional.

SUMMARY

An objective of the embodiments of the present invention is to at leastalleviate one or more of the aforesaid drawbacks evident in the priorart arrangements particularly in the context of manufacturing methodsand arrangements that allow for efficient integration of variouselectronic elements on a flat surface before shaping and coating orencapsulating it. The objective is generally achieved with a method ofmanufacture and corresponding arrangement for carrying out said methodin accordance with the present invention.

One of the advantageous aspects of the present invention is that itallows the electronic elements to be placed on a substantially flatsurface and then shape the surface housing the electronic elements fromflat to substantially, in practical circumstances, any desiredthree-dimensional shape. Even further, the invention comprises a methodand system for placing and attaching elements on a three-dimensionallyformable film in relation to the shape and design that the film is to bemolded.

Another advantageous aspect of the present invention is that itminimizes the need for layered film and coating film and sheetstructures, which are often the result of laminating layers, by usingonly one film to house electronics, graphical and other used content.

Another advantageous aspect of the invention is that the electroniccircuits and the elements may be attached on a flat surface, then testedthat the circuit and the elements work, before forming the substrateinto substantially three-dimensional according to any preferred shape.

In accordance with one aspect of the present invention a method formanufacturing an electromechanical structure, comprising:

-   -   producing conductors and/or graphics on a substantially flat        film,    -   attaching electronic and/or functional elements, e.g. MEMS, on        said film in relation to the desired three-dimensional shape of        the film,    -   forming the said film housing the electronic elements into a        substantially three-dimensional shape,    -   using the substantially three-dimensional film as an insert in        an injection molding process by molding substantially on said        film, wherein a preferred layer of material is attached on the        surface of the film, creating a electromechanical structure.

According to an exemplary embodiment of the invention the substantiallyflat film may be substantially flexible. According to an exemplaryembodiment of the invention the film comprises a substrate. According toan exemplary embodiment the film comprises a printed circuit board (PCB)or printed wiring board (PWB).

According to an exemplary embodiment of the invention the substantiallyflat film is preferably uniform and non-laminated, i.e. non-laminatedsheet. According to an exemplary embodiment of the invention thesubstantially flat film may comprise a laminated structure. According toan exemplary embodiment of the invention the substantially flat film maycomprise coating.

According to an exemplary embodiment of the invention, producingconductors on said film preferably comprises printing. According toanother exemplary embodiment of the invention, producing conductors onsaid film may comprise wiring. According to another exemplary embodimentof the invention, producing conductors on said film may comprisesoldering. According to another exemplary embodiment of the invention,producing conductors on said film may comprise using a printed circuitboard (PCB) or a printed wiring board (PWB).

According to an exemplary embodiment of the invention producing graphicson said film may preferably comprise printing. According to an exemplaryembodiment of the invention producing graphics on said film may comprisepainting.

According to an exemplary embodiment of the invention the electronicelements used may be electronic, electro-optic, electroacoustic,piezoelectric, electric, and/or electromechanical in nature. Accordingto another exemplary embodiment of the invention the electronic elementsmay comprise surface-mount technology (SMT), through-hole or flip-chipentities. According to another exemplary embodiment of the inventionsaid electronic elements may comprise substantially flexible components.According to a further exemplary embodiment of the invention theelectronic elements may be printed entities. According to anotherexemplary embodiment of the invention, wherein the electronic elementsmay be printed entities, said elements may be printed on thesubstantially flat film. According to further exemplary embodiment ofthe invention, wherein the electronic elements may be printed entities,said elements may be printed elsewhere (e.g. on a separate substratethat may be cut into suitable pieces after or before the printing),after which they may be attached ready-printed on the substantially flatfilm.

According to an exemplary embodiment of the invention the electronicelements may be attached to the film e.g. by optionally substantiallyflexible and/or conductive glue, paste or other adhesive. According toanother exemplary embodiment of the invention the elements may beattached by anchoring.

According to an exemplary embodiment of the invention attaching of theelectronic elements is done relative to the desired shape of the film.During the process of forming of the film from a substantially flat into three-dimensional, the film and the elements incorporated thereonundergo physical stress, such as strain, torque and compression. Theseforces are caused by not only the bending and stretching of the film butfrom the temperature needed for the process as well. The process ofattaching elements may, according to the present invention, comprisemany, individual or coincident, sequences.

According to an exemplary embodiment of the invention an optionalsequence of attaching the electronic elements may comprise, by forexample computer-aided modeling (CAD), model building orthree-dimensional surface strain measurement carried out for example byuniform square grid pattern or circular grid pattern or any othersuitable shaped pattern, for modeling the shape of the three-dimensionaldesign of the three-dimensional film. Modeling may comprise theparameters of strains, forces, dimensions, thermal and stress analysesas well as possible failures, such as fractures of the film caused bythe forming of the substantially flat film into substantiallythree-dimensional. Modeling may comprise stress analysis of thestructure. Modeling may comprise also manufacturing analysis for processsimulation of manufacturing processes, such as casting, molding andother forming manufacturing methods.

Another optional sequence of an exemplary embodiment of the inventionmay comprise choosing the orientation of the elements in relation to thesurface shapes of the three-dimensional film design. In general thismeans placing an element according to the shape of the surface, on whichit is to be attached on, so that the deformation of the flat surfacearea of the film relative to the surface area of the element against thesaid surface area of the film is as little as possible. Morespecifically, the magnitude of the curvature of the film surface, saidcurvature caused by the three-dimensional forming of the film, relativeto the facing element surface projection should be minimized. Settingthe orientation of an element according to the hypothetical curvature onthe three-dimensional surface, as the curvature and/or the strain causedby the deformation is not yet apparent in the element attachingsequence, so that the said curvature between and/or relative to theelements far edges or physical boundaries, on which it hasattaching/bounding contact to the film surface, and which is caused bythe three-dimensional forming of the film, causes as little separationand/or distance between the film surface and element bottom surfacerelative to the curved film surface.

Another optional sequence of an exemplary embodiment of the inventionmay comprise choosing the electronic element location in relation to thesurface shapes of the three-dimensional film design. In general thismeans placing an element according to the shape of the surface, on whichit is to be attached on, so that the deformation of the flat surfacearea of the film relative to the surface area of the film of the elementagainst the said surface area of the film deforms as little as possible.More specifically, the magnitude of the curvature and/or the strain ofthe film surface relative to the facing/bottom element surfaceprojection, said curvature caused by the three-dimensional forming ofthe film, should be minimized. By choosing the location of an element soit is placed on a surface that deforms as little as possible, as thecurvature caused by the deformation is not apparent in the elementattaching sequence, the element will go through less physical strains.Choosing the element location in relation to the film surface comprisesalso choosing locations wherein the element bottom relative to the filmsurface and the relative film surface touching surface is optimized, byfor example maximizing the touching surface areas. Choosing a goodlocation for an element accordingly to the film surface so means that anelement shouldn't be placed on the far edges of the film surface,wherein the element is partially over the ultimate edge of the surfaceof the film.

According to an exemplary aspect of the invention, some of the aspectscaused by the three-dimensional forming of the film on the elementsattached thereon may be alleviated by the optional use of substantiallyflexible elements.

According to another exemplary aspect of the invention, some of theaspects caused by the three-dimensional forming of the film on theelements attached thereon may be alleviated by the use of substantiallyflexible attaching means of the elements.

Another optional sequence of an exemplary embodiment of the invention ischoosing the elements in relation to the manufacturing parameters and interms of the physical properties, such as physical strength andtolerance to temperature and temperature changes as well as suitabilitywith different materials of the elements.

Another optional sequence of an exemplary embodiment of the inventioncomprises choosing the attaching method in accordance with flexibility,strength and so forth.

Another optional sequence of an exemplary embodiment of the inventioncomprises choosing the side on which the forming is done as well as theinjection molding and the injection molding type. Preferably theelements are attached on the side of film opposite to the side which isfor example pressed against a forming wall or molded on or over. Theelements may be however attached on the side which is molded on or over.

According to an exemplary embodiment of the present invention the filmand the elements thereon may be formed into a substantiallythree-dimensional shape preferably by thermoforming or vacuum forming.According to another exemplary embodiment of the invention the film andthe elements thereon may be formed into a substantiallythree-dimensional shape by blow molding or rotational molding.

Herein the three-dimensional essence of the formed structure may beunderstood in relation to the flat film's essential thickness amongother options. Three-dimensional form may be herein described as/throughdeviation, which is described hereinafter. The substantially flat filmcan be seen as to fit between two parallel planar (flat) surfaces, whichtake account even the slightest deformation on an even seemingly flatsurface. After the three-dimensional forming process the shape, in whichthe previously flat film has been formed in, can be also seen as to fitbetween two parallel surfaces. The distance, measured by the length ofthe line that extends maximally in between the two surfaces and inparallel with the normal of either surface against the other, yields theminimum distance that the surfaces can be situated from each otherwithout overlapping with film, both as substantially flat and asthree-dimensional. Said minimum distance between the two parallelsurfaces in both cases may be compared as to count the deviationpercentage. The deviation referred herein is so the ratio of theshortest distance between the two parallel surfaces that don't overlapwith the three-dimensionally formed film to the shortest distance of thesame film before the three-dimensional forming. Preferably, thedeviation is at least:

1. 2. 3. 4. Deviation 1.001 1.01 1.1 1 5. 6. 7. 8. Deviation 2 5 10 209. 10. 11. 12. Deviation 40 50 80 100 13. 14. 15. 16. Deviation 200 5001000 5000 17. 18. 19. 20. Deviation 10000 50000 100000 500000 21. 22.23. 24. Deviation 1000000 2000000 5000000 10000000

According to an exemplary embodiment of the present invention theinjection molding material is molded substantially exclusively partiallyover the film surfaces. Optionally injection molded material may bemolded on a surface portion of the film housing the electronic elements.Optionally the injection molded material may be molded on a surfaceportion of the film not housing electronic elements.

According to another exemplary embodiment of the present invention theinjection molded material, molded substantially on the said film,encapsulates the whole film.

According to another exemplary embodiment of the present invention theinjection molding may encapsulate the whole film but not the electronicelements.

According to another exemplary embodiment of the present invention theinjection molding may encapsulate the whole film and the electronicelements.

According to an exemplary embodiment of the present invention the methodmay comprise additional surface finishing or coating before or after anyof the sequences according to the said method.

In accordance with another aspect of the present invention anarrangement for carrying out said manufacturing method of anelectromechanical structure, comprising one or more of entities:

-   -   an entity for producing conductors and/or graphics on a surface,    -   an entity for attaching electronic elements on a surface,    -   an entity for forming a substantially flat film into a        substantially three-dimensional shape,    -   an entity for injection molding.

According to an exemplary embodiment of the invention, the arrangementcomprises an entity for producing conductors and/or graphics on asurface, which entity may comprise inkjet printer, screen printer, andwhich entity may be a roll-to-roll or a reel-to-reel machine.

According to an exemplary embodiment of the invention, the arrangementcomprises an entity for attaching electronic elements on a surface,which entity may comprise pick-and-place machine.

According to an exemplary embodiment of the invention, the arrangementcomprises an entity for forming a substantially flat film into asubstantially three-dimensional shape, which entity may comprise eithercontinuously roll-fed or automatically in precut pieces fed,thermoforming machine or vacuum former machine.

According to an exemplary embodiment of the invention, the arrangementcomprises an entity for injection molding, which entity may comprisehydraulic, mechanical, electric or hybrid injection molding machine.

According to another embodiment of the present invention theelectromechanical structure achieved by the method and correspondingarrangement may be for example an electronic device incorporating a userinterface (UI), such as a computer including desktop, laptop and palmtopdevices. According to another embodiment of the present invention theelectromechanical structure achieved by the method and correspondingarrangement may incorporate touchscreen or touch surface technology.

The previously presented considerations concerning the variousembodiments of the electronic device may be flexibly applied to theembodiments of the method mutatis mutandis and vice versa, as beingappreciated by a skilled person.

As briefly reviewed hereinbefore, the utility of the different aspectsof the present invention arises from a plurality of issues depending oneach particular embodiment. The manufacturing costs for producing theelectromechanical structure in accordance with the present invention toprovide a plurality of different functionalities may be kept low due torather extensive use of affordable and easily obtainable materials,elements, and process technology.

The electromechanical structure obtained by the method and correspondingarrangement is scalable in the limitations of the entities according tothe arrangement. The feasible process technology specifically providesfor rapid and agile industrial scale manufacturing of the device inaddition to mere prototyping scenarios.

The expression “a number of” may herein refer to any positive integerstarting from one (1). The expression “a plurality of” may refer to anypositive integer starting from two (2), respectively.

Different embodiments of the present invention are also disclosed in theattached dependent claims.

BRIEF DESCRIPTION OF THE RELATED DRAWINGS

Next, the embodiments of the present invention are more closely reviewedwith reference to the attached drawings, wherein

FIG. 1 is a flow diagram disclosing an embodiment of a method inaccordance with the present invention.

FIG. 2 illustrates the concept of forming film housing electronicelements three-dimensionally according to the present invention viaexemplary embodiments.

FIG. 3 is a block diagram of one embodiment of an arrangement comprisingentities in accordance with the present invention.

FIG. 4 illustrates an exemplary embodiment of the measurement used todescribe the three-dimensional essence of a formed structure inaccordance with the present invention.

FIG. 5 illustrates a block diagram of one feasible embodiment for anarrangement for carrying out a manufacturing method of the presentinvention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

With reference to FIG. 1, a flow diagram of one feasible embodiment formanufacturing the solution of the present invention.

At 102, referring to a start-up phase, the necessary tasks such asmaterial, element and tools selection and acquisition take place. Indetermining the suitable elements and other components/electronics,specific care must be taken that the individual components and materialselections work together and survive the selected manufacturing processof the overall arrangement, which is naturally preferably checkedup-front on the basis of the manufacturing process vs. element datasheets, or by analyzing the produced prototypes, for example.

At 104, a substantially flat film is produced according to a preferredshape and size and then cleaned. Said film is preferably substantiallythin sheet. The film comprises preferably polycarbonate (PC) orpolyethylene terephthalate (PET) because these materials possess themost suitable thermoforming window (i.e. in which the material becomessubstantially pliable for stretching and shaping) and flexibilityrequired for efficient three-dimensional forming. The film material mayoptionally comprise other materials suitable according to the endproduct requirements and manufacturing requirements, such as for exampleflexibility, robustness, thermoforming window, strength, adhesionproperties and other material properties in view of the electronics andthe adjacent materials, or e.g. in view of available manufacturingtechniques, are met. Said other materials may comprise other plastics,silicon, rubber, or a mixture of these. Further feasible materialscomprise polymethyl methacrylate (PMMA), acrylonitrile-butadiene-styrene(ABS), Glycolized polyethylene terephthalate (PETG), high impactpolystyrene (HIPS), high-density polyethylene (HDPE), acrylic polymer ora mixture of these. Thickness of the film may vary according toproperties required from the film, such as material strength,flexibility, elasticity, transparency and/or size required from thefinal product. The film may contain a number of recesses, cavities, orholes for accommodating electronics such as electronic circuits,conductors, or component leads and/or sockets, etc.

The selected film may also be preconditioned prior to and/or during theillustrated processing phases. The film may be pre-conditioned toincrease adhesion with other materials such as injection molded coverplastics, for example.

Optionally printed circuit board (PCB) or printed wiring board (PWB),with material, shape and size requirements according to the previouslyaforementioned film material requirements, may be chosen as the film.

At 106, conductors and/or graphics are produced on the film. The filmmay so comprise only conductors, only graphics or both conductors andgraphics. Producing said conductors and/or graphics is preferably doneby exploiting suitable printing technologies. E.g. an inkjet printer orother applicable device may be used to print said conductors and/orgraphics on the film. Preferably one device is used for producing bothconductors and graphics. Optionally different devices for producingconductors and producing graphics may also be used.

Generally, feasible techniques for printing conductors and graphics mayinclude screen printing, rotary screen printing, gravure printing,flexography, ink-jet printing, tampo printing, etching (like withPWB-substrates, printed wiring board), transferlaminating, thin-filmdeposition, etc. For instance, in the context of conductive pastes,silver-based PTF (Polymer Thick Film) paste could be utilized for screenprinting the desired circuit design on the film. Also e.g. copper orcarbon-based PTF pastes may be used. Alternatively, copper/aluminumlayers may be obtained by etching. In a further alternative, conductiveLTCC (low temperature co-fired ceramic) or HTCC (high temperatureco-fired ceramic) pastes may be sintered onto the film. One shall takeinto account the properties of the film when selecting the material forconductors. For example, sintering temperature of LTCC pastes may beabout 850 to 900° C., which may require using ceramic films. Further,silver/gold-based nanoparticle inks may be used for producing theconductors.

The paste/ink shall be preferably selected in connection with theprinting technique and the film material because different printingtechniques require different rheological properties from the usedink/paste, for instance. Further, different printing technologiesprovide varying amounts of ink/paste per time unit, which often affectsthe achievable conductivity figures.

Alternatively, the conductors and/or graphics may be provided within thefilm.

At 108, electronic components are attached on the film. Said electroniccomponents are preferably surface-mount technology (SMTs), through-hole,flip-chip or printed entities. Optionally, the elements may be producedby exploiting suitable printing procedures as depicted in the phase 106.Printed elements may be optionally produced on the substantially flatfilm by printing on said film. Printed elements may be optionallyproduced separate from the substantially flat film by printing on asubstrate, after which, the whole substrate or preferred pieces of thesubstrate comprising elements, may be attached on the substantially flatfilm.

SMT, though-hole, flip-chip and printed entities may be attached usingoptionally substantially flexible means by anchoring, gluing or by otheradhesive, such as an epoxy adhesive. Both conductive (for enablingelectrical contact) and non-conductive (for mere fixing) adhesives maybe utilized. Said components may be selected by their technology andfunctions as well as so as to withstand the pressure and temperature ofthe utilized three-dimensional forming, such as the thermoforming orvacuum forming process, as well as the housing component-establishingprocess, such as injection molding process.

As an example, said elements may be electronic, electro-optic,electroacoustic, piezoelectric, electric, and/or electromechanical bynature, or at least comprise such components. Further on such elementsand/or components may comprise control circuits, touch sensing such asstrain, resistive, capacitive, (F)TIR and optical sensing components,tactile components and/or vibration components such as piezoelectricactuators or vibration motors, light-emitting components such as(O)LEDs, sound-emitting and or sound-receiving such as microphones andspeakers, device operating parts such as memory chips, programmablelogic chips and CPU (central processing unit), other processing devicessuch as digital signal processors (DSP), ALS devices, PS devices,processing devices (microprocessor, microcontroller, digital signalprocessor (DSP)), MEMS and/or various still unmentioned sensors. Indeed,a myriad of technologies may be implemented and structure may comprisevarious additional components, in addition to the disclosed ones. Asbeing appreciated by skilled readers, also the configuration of thedisclosed components may differ from the explicitly depicted onedepending on the requirements of each intended use scenario wherein thepresent invention may be capitalized.

Optionally, the elements may be attached and configured in apredetermined, systematic, e.g. symmetric or matrix, formation.

Alternatively, the electronic elements may be provided within the film.

At 110, the film is formed from substantially flat into substantiallythree-dimensional. The said forming may be preferably done bythermoforming, using vacuum forming or pressure forming. Alternatively,said forming may be done by billow forming, drape forming, blow molding,pre or rotational molding.

Thermoforming as a process comprises heating the film into thethermoforming window (i.e. in which the material becomes substantiallypliable for stretching and shaping), placing the film into a mold,applying vacuum in order to press the film against the mold so that thefilm mold to the shape of the mold, letting the film cool down while atthe same time applying the vacuum and ejecting the cooled down film,which has now adapted the desired shape according to the mold, byreleasing the vacuum and/or applying “air-eject” for easier removal ofthe film. Additionally optionally, a cutting of the film e.g. to apreferred size or for better finish may be carried out before or afterthe thermoforming. The heating of the film into the thermoforming windowmay be optionally done inside the thermoforming machine e.g. in the moldor outside the thermoforming machine e.g. in an oven.

Considering the parameters and set-up of the preferred thermoformingprocess using vacuum or pressure, few further guidelines can be given asmere examples as being understood by the skilled persons. Few examplesfor the lower limit of the thermoforming temperature include: PC 150°C., PET 70° C., ABS 88° C.-120° C. The pressure applied on the filmobtained either by pressing mechanically air into the mold or by suckinga vacuum into the mold should be roughly over some 100 psi for a singlelayer film construction whereas it should be roughly over some 200 psifor laminated structures. The used three-dimensional film and theprocess parameters shall be preferably selected such that said film doesnot melt. The film shall be positioned in the mold such that it remainsproperly fixed however so that the fixed points doesn't hinder theforming.

At 112, the assembly comprising the preferred elements attached to thenow three-dimensional film is placed as an insert into a mold frame andinjection molded.

The injection molding material molded over the three-dimensional film isoptionally transparent and may comprise polymers such as polycarbonate(PC), polyethylene terephthalate (PET), polymethyl methacrylate (PMMA),polyamide (PA), cyclo olefin copolymer (COC), cyclo olefin polymer(COP), polytetrafluoroethylene (PTFE), polyvinyl chloride (PVC) or amixture of these. Alternatively or additionally, the material mayinclude glass. An applicable layer material shall be generally selectedsuch that the desired flexibility, robustness, and other requirementslike adhesion properties in view of the electronics and the adjacentmaterials, or e.g. in view of available manufacturing techniques, aremet.

Considering the process parameters and set-up, few further guidelinescan be given as mere examples as being understood by the skilledpersons. When the three-dimensional film is PET and the plastics to be,for example, injection molded thereon is PC, the temperature of themelted PC may be about 280 to 320° C. and mold temperature about 20 to95° C., e.g. about 80° C. The used three-dimensional film and theprocess parameters shall be preferably selected such that said film doesnot melt and remains substantially solid during the process. The filmshall be positioned in the mold such that it remains properly fixed.Likewise, the preinstalled components, graphics and/or electronics shallbe attached to the substrate such that they remain static during themolding.

The injection phase of the injection mold process comprises heating amaterial, chosen accordingly to the desired features, until molten, andthen force injecting said material into the mold, wherein it sets on theinsert. Preferably the injection molded material may be moldedsubstantially exclusively partially over the film surfaces, which maycomprise either molding on a surface portion of the film housing thepreinstalled components, graphics and/or electronics or molding on asurface portion of the film not housing the preinstalled components,graphics and/or electronics. Optionally, the injection molded materialmay be molded substantially on the said film such that it encapsulatesthe whole film, which may comprise either that the molding encapsulatesonly partially the preinstalled components, graphics and/or electronicsor that the molding encapsulates preinstalled components, graphicsand/or electronics so that the preinstalled components, graphics and/orelectronics are fully embedded inside the mold.

Generally in the embodiments of the present invention, the thickness ofthe established housing as well as the installation depth of saidelements and electronics in the housing may be varied according to theapplication so that they may form a part of the surface (inner or outersurface of the overall electronic device) thereof or be completelyembedded, or ‘hidden’, inside the housing. This enables customization ofthe toughness, elasticity, transparency, etc., of the constructedelectromechanical structure as a whole as well as customization of themaintenance capabilities and protection of said embedded elements.Embedding the elements completely inside the housing typically providesbetter protection. Optionally leaving the elements to the surfaceprovides less protection but enables easier maintenance or replacementof said elements. Depending on the application certain elements may beembedded entirely, when other elements are only partially embedded.

After the injection process the injected material is kept under apressure and let to cool down, after which it may be taken out.

At 114, the method execution is ended. Further actions such as elementregulation, quality control, surface treatment and/or finishing orfurbishing may take place.

The use of advantageously flexible materials enables at least some ofthe method items to be carried out by roll-to-roll methods, which mayprovide additional benefits time-, cost- and even space-wise consideringe.g. transportation and storage. In roll-to-roll or ‘reel-to-reel’methods the desired entities, such as conductors, graphics and/orelectronic elements, may be deposited on a continuous ‘roll’ substrate,which may be both long and wide, advancing either in constant or dynamicspeed from a source roll, or a plurality of source rolls, to adestination roll during the procedure. The film may thus comprisemultiple products that are to be cut separate later.

Roll-to-roll or ‘reel-to-reel’ methods may thus be used to combine atleast two of the method steps 102, 104, 106, 108. All of the methodsteps 102, 104, 106, 108, i.e. substantially all of the method steps maybe carried out by roll-to-roll or ‘reel-to-reel’ methods. Optionally allof the method steps (102-114), i.e. the whole as a whole, may be carriedout by roll-to-roll or ‘reel-to-reel’ methods.

The roll-to-roll manufacturing advantageously enables rapid and costeffective manufacturing of products also in accordance with the presentinvention. During the roll-to-roll process several material layers maybe joined together ‘on the fly’, and the aforesaid conductors, graphicsand/or electronic elements may be structured on them prior to, upon, orafter the actual joining instant. The source layers and the resultingband-like aggregate entity may be further subjected to varioustreatments during the process. Layer thicknesses and optionally alsoother properties should be selected so as to enable roll-to-rollprocessing to a preferred extent.

FIG. 2 illustrates four different exemplary side views 202 a, 202 b, 202c, 202 d of the film with the electronic elements attached thereon.

View 202 a illustrates the substantially flat film 210 housing theattached electronic elements 204 a & 20 b and the conductors 206 and thegraphics 208 thereon before forming said film from substantially flatinto three-dimensional.

View 202 b illustrates an example of a three-dimensional film 212, i.e.the film that was substantially flat before the forming process, housingthe attached electronic elements 204 a & 204 b and the conductors 206and the graphics 208 thereon. In this embodiment the film has beenformed into a simple arch shape.

View 202 c illustrates an example of a three-dimensional film 212, i.e.the film that was substantially flat before the forming process, housingthe attached electronic elements 204 a & 204 b and the conductors 206and the graphics 208 thereon. In this embodiment the film has beenformed into an undulating shape.

View 202 d illustrates an example of a three-dimensional film 212, i.e.the substantially flat film after the forming process, housing theattached electronic elements 204 a & 204 b and the conductors 206 andthe graphics 208 thereon. In this embodiment the film has been moldedinto an asymmetric arch form.

The shape and size of the three-dimensionally formed film 212 is notrestricted to any particular shape and may thus be manufactured to fit awide range of applications.

FIG. 3 is an axonometric illustration of an exemplary embodiment of athree-dimensional shape achieved by the forming process. Said embodimentcomprises a film 306 housing the attached electronic elements 304 a, 304b, 304 c & 304 d and the conductors and the graphics thereon (notexplicitly depicted). In this embodiment the film has been molded intoasymmetric wave-like form.

The shape and size of the three-dimensionally formed film 306 is notrestricted to any particular form and may thus be manufactured to fit awide range of applications.

FIG. 4 illustrates an exemplary embodiment of the measurement used todescribe the three-dimensional essence of the formed structure.Three-dimensional form may be herein described as/through deviation,which is described herein. The substantially flat film can be seen as tofit between two parallel planar (flat) surfaces 402 a & 404 a, whichtake account even the slightest deformation on an even seemingly flatsurface. After the three-dimensional forming process the shape, in whichthe previously flat film has been formed in, can be also seen as to fitbetween two parallel surfaces 402 b & 404 b. The distances d1 and d2,measured by the length of the line that extends maximally in between thetwo surfaces and in parallel with the normal of either surface againstthe other, yields the minimum distance that the surfaces can be situatedfrom each other without overlapping with film, both as substantiallyflat and as three-dimensional. Said minimum distance between the twoparallel surfaces in both cases may be compared as to count thedeviation ratio. The deviation referred herein is so the ratio of theshortest distance d2 between the two parallel surfaces 402 b & 404 bthat don't overlap with the three-dimensionally formed film to theshortest distance d1 between the two parallel surfaces 402 a & 404 athat don't overlap with the substantially flat film before thethree-dimensional forming. Preferably, the deviation ratio d2/d1 ispreferably at least in correspondence to the numeric values presentedherein before.

FIG. 5 illustrates a block diagram of one feasible embodiment for anarrangement 500 for carrying out the said manufacturing method of thepresent invention.

Block 502 represents an entity for producing conductors and/or graphicson a surface. Such entity may comprise a machine from at least one ofthe following: inkjet printer, screen printer, which may be roll-to-rollor reel-to-reel machines.

Block 504 represents an entity for attaching electronic elements on asurface. Such entity may comprise a pick-and-place machine.Pick-and-place machines are widely known and especially suitable hereinbecause they allow fast and precise attaching of various differentcomponents and are highly flexible through programming.

Block 506 represents an entity for forming a substantially flat filminto a substantially three-dimensional shape. Such entity may compriseeither continuously roll-fed or automatically in-precut-pieces-fed,optionally computer numerical control (CNC) machine, thermoformingmachine, vacuum former machine, pressure forming machine or blow moldingmachine or a combination of these.

Block 508 represents an entity for injection molding. Such an entity maycomprise hydraulic, mechanical, electric or hybrid injection moldingmachine or a combination of these.

The scope of the invention is determined by the attached claims togetherwith the equivalents thereof. The skilled persons will again appreciatethe fact that the disclosed embodiments were constructed forillustrative purposes only, and the innovative fulcrum reviewed hereinwill cover further embodiments, embodiment combinations, variations andequivalents that better suit each particular use case of the invention.

The invention claimed is:
 1. A method for manufacturing anelectromechanical structure, comprising: producing conductors on a flatfilm; determining a strain force of the flat film in a hypotheticalthree-dimensional shape thereof; selecting locations of a plurality oflocations along the flat film to attach electronic elements based on anamount of the strain force determined to occur in the hypotheticalthree-dimensional shape of the flat film; attaching the electronicelements on the flat film at the selected locations along the flat filmso that the selected locations exhibit less of the strain force when theflat film is formed into a three-dimensional film than at least someother locations along the flat film when the flat film is formed intothe three-dimensional film; forming the flat film into thethree-dimensional film so that the three-dimensional film has athree-dimensional shape corresponding to the hypotheticalthree-dimensional shape of the flat film; and injection molding materialon the three-dimensional film.
 2. The method of claim 1, wherein theflat film is a substrate.
 3. The method of claim 2, wherein thesubstrate is a printed circuit board (PCB) or a printed wiring board(PWB).
 4. The method of claim 1, wherein the flat film is flexible. 5.The method of claim 1, wherein the flat film comprises at least one ofpolyethylene terephthalate (PET), polymethyl methacrylate (PMMA),polycarbonate (PC), acrylonitrile-butadiene-styrene (ABS), Glycolizedpolyethylene terephthalate (PETG), high impact polystyrene (HIPS),high-density polyethylene (HDPE), acrylic polymer, or a mixture ofthese.
 6. The method of claim 1, wherein producing the conductors on theflat film includes printing by a printing technique chosen from a groupconsisting of screen printing, rotary screen printing, gravure printing,flexography, jet printing, tampo printing, etching, transfer laminating,and thin-film deposition.
 7. The method of claim 1, wherein the attachedelectronic elements further include through-hole, flip-chip, or printedentities.
 8. The method of claim 1, wherein attaching the electronicelements on the flat film includes printing the electronic elements onthe flat film.
 9. The method of claim 1, further comprising printing theelectronic elements on a substrate and thereafter attaching thesubstrate to the flat film.
 10. The method of claim 1, wherein attachingthe electronic elements includes flexibly attaching the electronicelements by anchoring, gluing, or other adhesive.
 11. The method ofclaim 1, wherein producing the conductors on the flat film and attachingthe electronic elements on the flat film include a continuousroll-to-roll process.
 12. The method of claim 1, wherein forming theflat film into the three-dimensional film includes a thermoformingprocess selected from the group consisting of vacuum forming, pressureforming, billow forming, drape forming, blow molding, pre molding, androtational molding.
 13. The method of claim 1, further comprisingcoating the electromechanical structure.
 14. The method of claim 1,further comprising producing the conductors on the flat film andattaching the electronic elements on the flat film include areel-to-reel process.